CN108349311B

CN108349311B - Pneumatic tire and crosslinked rubber composition

Info

Publication number: CN108349311B
Application number: CN201680060333.0A
Authority: CN
Inventors: 间下亮; 岸本浩通; 北乡亮太
Original assignee: Sumitomo Rubber Industries Ltd
Current assignee: Sumitomo Rubber Industries Ltd
Priority date: 2015-10-27
Filing date: 2016-10-21
Publication date: 2019-07-30
Anticipated expiration: 2036-10-21
Also published as: EP3348426A4; EP3348426B1; CN108349311A; WO2017073494A1; EP3348426A1; US20180304683A1; US11440349B2

Abstract

The present invention provides wearability outstanding pneumatic tire and crosslinked rubber composition, the pneumatic tire is characterized in that, it include: the bead core being separately positioned in pair of right and left bead part, two bead parts are extended to via two sides wall portion from crown part and are fixed on the casingply of the bead core, the liner layer located more in the inner part on tire diameter direction than the casingply is set and the tyre surface at place more more outward than the casingply on tire diameter direction is set, the tyre surface has the volume of 35% or more density regions when stretching under the application stress of 1.5MPa, the volume of 7.5% gap section below when being stretched under the application stress of 3.0MPa, -20 DEG C of glass transition temperatures below, the crosslinked rubber composition has 3 when stretching under the application stress of 1.5MPa The volume of 5% or more density regions, the volume and -20 DEG C of glass transition temperatures below of 7.5% gap section below when being stretched under the application stress of 3.0MPa.

Description

Pneumatic tire and crosslinked rubber composition

Technical field

The present invention relates to pneumatic tires and crosslinked rubber composition.

Background technique

It is generally known for the crosslinked rubber composition of the tire tread (example when its glass transition temperature (Tg) is lower Such as, patent document 1 etc.), there is excellent fracture resistance and wearability.One of factor is considered as, and when Tg is lower, hands over Join rubber composition reduces by the elasticity modulus within the scope of Uneven road frequency of stimulation caused by smooth, this to be crosslinked rubber group Closing object can be easy to follow unevenness.

However, low Tg not necessarily will lead to excellent fracture resistance and wearability, and there is exception.In other words, have When there are such phenomenons: although the hardness of crosslinked rubber composition is high, by measuring the crosslinked rubber composition and its rubber The wearability of glue product has been found that the result that cannot have been obtained.

In order to make the mechanism of production of the exception clear, fracture and friction phenomenon are looked into see by various methods.However, Mechanism is not yet completely understood.

Also, it is known that X ray computer tomography is as analyzing the material and packet that are made of solid sample Technology containing density regions inside it.For example, patent document 2 describes what a kind of visual analysis was made of friction member The method of material and the density regions in the portion that is contained within.It is applied however, being in patent document 2 without descriptive analysis The specimen material of the state of external energy such as tensional state or the density of analysis of material.

Patent document

Patent document 1:JP2013-007025 A

Patent document 2:JP2009-085732A

Summary of the invention

The problem to be solved in the present invention

The object of the present invention is to provide the excellent pneumatic tire of wearability and crosslinked rubber compositions.

The means solved the problems, such as

The present inventor has made intensive studies, as a result, it has been found that, it is stretched by increasing in the case where 1.5MPa applies stress When density regions, reduce 3.0MPa apply stress under stretch when gap section, and reduce glass transition temperature, It can inhibit the growth of the crackle generated inside crosslinked rubber composition and can be further improved wearability, to complete The present invention.

That is, the pneumatic tire includes being separately positioned in pair of right and left bead part the present invention relates to a kind of pneumatic tire Bead core, from crown part via two sides wall portion extend to two bead parts and be fixed on the bead core casingply, The liner layer located more in the inner part on tire diameter direction than the casingply is set and is arranged in tire diameter direction On place more more outward than the casingply tyre surface, the tyre surface has 35% when being stretched through the application stress of 1.5MPa Above density regions volume, 7.5% gap section volume below, -20 DEG C when being stretched through the application stress of 3.0MPa Glass transition temperature below.

In addition, the present invention relates to a kind of crosslinked rubber composition, and the crosslinked rubber composition has in 1.5MPa The density regions volume for applying when stress stretches 35% or more, it is 7.5% below when the application stress of 3.0MPa stretches Gap section volume and -20 DEG C of glass transition temperatures below.

Preferably, the rubber components include one or more rubber components containing conjugated diene compound.

Preferably, above-mentioned density regions are 0.1~0.8 times that density is the density of crosslinked rubber composition before stretching Region.

Preferably, above-mentioned gap section is 0~0.1 times of the area that density is the density of crosslinked rubber composition before stretching Domain.

Preferably, the method for evaluating density regions volume and gap section volume is X ray computer tomography.

Preferably, the die-away time of the fluorophor for X-ray to be converted to visible light is 100ms or less.

Preferably, the brightness of X-ray is 10¹⁰Photon/s/mrad²/mm²/ 0.1%bw or more.

Technical effect of the invention

Pneumatic tires according to the present invention includes tyre surface, and the tyre surface has big when stretching under 1.5MPa applies stress The density regions of volume, the gap section of the small size when being stretched under 3.0MPa applies stress and reduced TG transformation temperature Degree and crosslinked rubber composition according to the present invention have the low-density of the large volume when stretching under 1.5MPa applies stress Region, the gap section of the small size when being stretched under 3.0MPa applies stress and lower glass transition temperatures, therefore can provide The excellent pneumatic tire of wearability and crosslinked rubber composition.

Detailed description of the invention

Fig. 1 is one embodiment for evaluating the evaluating apparatus of Density Distribution of the crosslinked rubber composition in its stretching Perspective illustration.

Fig. 2 is the process for showing the process steps of evaluation method of Density Distribution of the crosslinked rubber composition in its stretching Figure.

Symbol description

1 evaluating apparatus

2 stress bringing devices

3 filming apparatus

4 evaluating apparatus

10 rubber testing pieces

Specific embodiment

Crosslinked rubber composition of the invention is to meet the crosslinked rubber composition of following condition: having and applies in 1.5MPa Under stress stretch when large volume density regions, 3.0MPa apply stress under stretch when small size gap section and Lower glass transition temperatures (Tg).It should be noted that crosslinked rubber composition used herein is using vulcanizing agent and organic mistake The rubber composition that oxide is crosslinked.

Rubber components

Above-mentioned rubber components are not particularly limited, and are including the rubber components of the following rubber used in rubber industry In: diene series rubber such as isoprene rubber, butadiene rubber (BR), SBR styrene butadiene rubbers (SBR), styrene-is different Pentadiene-butadiene rubber (SIBR), neoprene (CR), acrylonitrile-butadiene rubber (NBR) and butyl rubber, Ke Yishi When selection and use one or more.It is particularly preferred that it includes conjugated diene that rubber components, which include one or more of, The rubber components of object are closed, and from fuel efficiency, wearability from the viewpoint of the balance of durability and wet adherence properties, is preferably wrapped Rubber components containing SBR and BR, from the Tg of rubber components it is lower from the viewpoint of, more preferable rubber components include BR.

SBR is not particularly limited, and the example includes the SBR (E-SBR) of emulsion polymerization, the SBR (S-SBR) of polymerisation in solution Deng.SBR can be oil-filled or non-oil-filled.Further, it is also possible to using there is enhancing and filler interaction ability Terminal-modified S-SBR and backbone modification S-SBR.These SBR can be used alone or can be applied in combination with two or more.

From the viewpoint of grip performance, the styrene-content of SBR is preferably not less than 16 mass %, and more preferably no less than 20 Quality % is further preferably not less than 25 mass %, is particularly preferably not less than 30 mass %.When styrene-content is too big, benzene Vinyl group becomes closer to each other, and polymer becomes too hard and be crosslinked to become uneven, this may to run at high temperature The foaminess of period is deteriorated, and further exists since the temperature dependency of performance increases and performance is relative to temperature change It is widely varied so the trend of stable grip performance cannot be obtained in the middle and later periods of traveling.Therefore, styrene-content is preferred No more than 60 mass %, more preferably no more than 50 mass %, further preferably it is no more than 40 mass %.It should be noted that herein The styrene-content of SBR used according to¹H-NMR measurement calculates.

From the viewpoint of the Hs and grip performance of crosslinked rubber composition, the contents of ethylene of SBR is preferably not less than 10%, more preferably no less than 15%.On the other hand, from the viewpoint of grip performance, EB (durability) and wearability, SBR's Contents of ethylene is preferably more than 90%, more preferably no more than 80%, is further preferably no more than 70%, is particularly preferably no more than 60%.It should be noted that the contents of ethylene (amount of 1,2- key butadiene unit) of SBR used herein can be by infrared Absorption spectrum analyzing method determines.

The glass transition temperature (Tg) of SBR is preferably not less than -45 DEG C, more desirably not less than -40 DEG C.From preventing temperature band Winter during from the viewpoint of crackle caused by embrittlement, Tg is preferably no greater than 10 DEG C, and Tg is more preferably no higher than 5 DEG C.It should infuse Meaning, the glass transition temperature of SBR used herein is according to JIS K 7121, in 10 DEG C/min of heating rate item The value measured under part by carrying out differential scanning calorimetry measuring method (DSC).

From the viewpoint of grip performance and foaminess, the weight average molecular weight (Mw) of SBR is preferably not less than 700,000, more Preferably not less than 900,000, further preferably it is not less than 1,000,000.On the other hand, from the point of view of foaminess, weight is equal Molecular weight is preferably more than 2,000,000, more preferably no more than 1,800,000.It should be noted that used in the present invention The weight average molecular weight of SBR can be based on gel permeation chromatography (GPC) (the GPC-8000 system of Tosoh Corporation manufacture Column；Detector: differential refractometer；Column: the TSKGEL SUPERMALTPORE HZ-M manufactured by Tosoh Corporation) really Fixed measured value is obtained using standard polystyrene calibration.

For the reason of can obtain enough grip performances, the SBR content in rubber components is preferably not less than 30 matter Measure %, more preferably no less than 40 mass %.On the other hand, from the viewpoint of wearability, grip performance and fuel efficiency, SBR Content is preferably more than 90 mass %, more preferably no more than 85 mass %, is further preferably no more than 80 mass %.

Especially for the reason of can be realized higher grip performance and foaminess, preferred rubber component contains 40 matter The SBR with 16~60 mass % styrene-contents of % or more is measured, more preferable rubber components contain the tool of 50 mass % or more There is the SBR of 25~55 mass % styrene-contents.

BR is not particularly limited, and the BR (high-cis BR) with high cis-contents can be used for example for example from ZEON The BR1220 of CORPORATION；From Ube Industries, the BR130B of Ltd., BR150B；Modified BR such as comes from ZEON The BR1250H of CORPORATION；BR with syndiotactic polybutadiene crystal, such as from Ube Industries, Ltd. VCR412 and VCR617；The BR (rare earth BR) synthesized using rare earth element catalyst is for example from LANXESS Japan's BUNA-CB25 etc..These BR can be used alone or can be used in combination.In view of processability and excellent resistance to Mill property and fracture resistance, particularly preferred high-cis BR and rare earth BR.

When rubber components include BR, reduced from Tg, wearability, from the viewpoint of grip performance and fuel efficiency, rubber BR content in component is preferably not less than 10 mass %, more desirably not less than 15 mass %, further much more desirably not less than 20 matter Measure %.In addition, from the viewpoint of grip performance and fuel efficiency, the content of BR is preferably more than 70 mass %, more from wearability Preferably more than 60 mass %.

Above-mentioned filler can be from commonly used in optionally selecting in those of in crosslinked rubber composition, and carbon black and two Silica is preferred.

The example of carbon black includes that furnace black, acetylene black, thermal crack black, channel black, graphite etc., and these carbon blacks can be with Exclusive use being applied in combination with two or more.Wherein, furnace black is preferably as can mention well balancedly Property at high and low temperature and wearability.

From the viewpoint of obtaining sufficient enhancement and wearability, the N2 adsorption specific surface area (N of carbon black₂SA) preferably not Less than 70m²/ g, more preferably no less than 90m²/g.In addition, it is excellent from dispersibility, it is not easy from the perspective of the performance generated heat, carbon black N₂SA is preferably 300m²/ g is hereinafter, more preferably 250m²/ g or less.It should be noted that carbon black used herein N₂SA is according to JIS K6217-2 " rubber industry carbon black-fundamental characteristics-part 2: measurement-nitrogen adsorption method-of specific surface area Single-point method " is measured.

When rubber composition includes carbon black, in terms of 100 mass parts of rubber components, content is preferably not less than 3 mass parts, More preferably no less than 4 mass parts.When its content is less than 3 mass parts, there is the trend that cannot obtain enough enhancements.It is another Aspect, the content of carbon black are preferably more than 200 mass parts, more preferably no more than 150 mass parts, are further preferably no more than 60 matter Measure part.When its content is more than 200 mass parts, it is intended to which processability reduces, and is easy to produce fever, and wearability reduces.

Silica is not particularly limited, for example, dry process silica (anhydride silica) and wet process preparation Silica (aqueous silicon dioxide), and aqueous silicon dioxide is due to preferred containing a large amount of silanols.

From the viewpoint of durability and elongation at break, the N2 adsorption specific surface area (N of silica₂SA) preferably not small In 80m²/ g, more preferably no less than 100m²/g.On the other hand, from the viewpoint of fuel efficiency and processability, silica N₂SA is preferably no greater than 250m²/ g, more preferably no more than 220m²/g.It is worth noting that, silica used herein N₂SA is the value measured according to ASTM D3037-93.

When rubber composition includes silica, from the point of view of durability and elongation at break, with rubber components For 100 mass parts meters, the content of silica is preferably not less than 5 mass parts, more preferably no less than 10 mass parts.On the other hand, From the dispersibility improved when being kneaded and inhibit reuniting again because of the silica during storing during calendering heating and after calendering Caused by from the perspective of processability reduces, the content of silica is preferably 200 below the mass more preferably 150 matter Measure part or less.

When rubber composition includes silica, preferably silica and silane coupling agent are applied in combination.It can make The arbitrary silane coupling agent used in rubber industry with silica composition as silane coupling agent of the present invention, Example includes the Si75 of sulfidosilane coupling agent such as Evonik Degussa manufacture, Si266 (bis- (3- triethoxy-silicanes Base propyl) disulphide) and the Si69 that is manufactured by Evonik Degussa (bis- (3- triethoxysilylpropyltetrasulfides) four vulcanize Object)；Mercaptosilane coupling agents (silane coupling agent containing sulfydryl) such as 3-mercaptopropyi trimethoxy silane, by Momentive NXT-Z100, NXT-Z45 and the NXT of Performance Materials manufacture；Vinyl silicane coupling agent such as vinyl three Ethoxysilane；Amino silicane coupling agent such as 3-aminopropyltriethoxysilane；Glycidoxy silane coupling agent is for example γ-glycidoxypropyl triethoxysilane；Nitro silane coupling agent such as 3- nitropropyl trimethoxy silane；And Chloro silane coupling agents such as 3- r-chloropropyl trimethoxyl silane.These silane coupling agents can be used alone, and can also combine two Kind or two or more uses.Wherein, from silica strong binding force and excellent low heat generation characteristic from the viewpoint of, vulcanization Silane coupling agent and mercaptosilane coupling agents are preferred.

When rubber composition include silane coupling agent when, by silica be 100 mass parts in terms of, the content of silane coupling agent Preferably not less than 2 mass parts, more preferably no less than 3 mass parts.When the content of silane coupling agent is less than 2 mass parts, tend to not The effect for improving silica dispersion can sufficiently be obtained.On the other hand, the content of silane coupling agent is preferably more than 25 mass parts, More preferably no more than 20 mass parts.When the content of silane coupling agent is more than 25 mass parts, tend to the effect that cannot obtain cost.

In addition to the aforementioned components, crosslinked rubber composition according to the present invention, which may include, is commonly used to manufacture crosslinking rubber The compounding agent of glue composition, such as resin Composition, oil, zinc oxide, stearic acid, antioxidant, wax, sulphur donor, vulcanizing agent, vulcanization Promotor etc..

Crosslinked rubber composition of the invention is characterized in that, density regions when being stretched through the application stress of 1.5MPa Volume be 35% or more, be 7.5% hereinafter, and glass by the volume for applying gap section when stress stretches of 3.0MPa Glass transition temperature is -20 DEG C or less.

In the crosslinked rubber composition of the density regions with large volume, therefore cross-linked structure high uniformity is answered Power be not concentrated in specific region but disperse.The cross-linked rubber composition in the region of the gap section of the generation with small size Object has the durability such as fracture resistance and wearability for excellently fighting external stress.In addition, having lower glass transition temperatures Crosslinked rubber composition have to the good followability in uneven road surface.Because passing through applying when stress stretches for 1.5MPa The volume of density regions is big, by 3.0MPa apply stress stretch when gap section it is small in size, and vitrifying turn Temperature is low, so high-wearing feature may be implemented in crosslinked rubber composition according to the present invention.

The volume of density regions when being stretched through the application stress of 1.5MPa is preferably 40% or more.On the other hand, The volume of density regions when being stretched through the application stress of 1.5MPa is preferably 95% or less.

The volume of gap section when being stretched through the application stress of 3.0MPa is preferably 7.0% or less.

In order to realize 35% or more the volume for applying density regions when stress stretches made through 1.5MPa, and The volume of gap section when being stretched through the application stress of 3.0MPa is 7.5% hereinafter, it is necessary to make in rubber composition Cross-linked state is uniform.As the example for the method that the cross-linked state made in rubber composition homogenizes, including increase mixing time Or increase compounding procedure number, to make the uniform method of the dispersity of vulcanizing agent and/or vulcanization accelerator.

It is explained below density regions and gap section.Firstly, if the stress for being applied to crosslinked rubber composition is super The intrinsic critical value of crosslinked rubber composition is crossed, then the deviation of density generates in crosslinked rubber composition, thus produces inside it Raw density regions.There are reversible part and irreversible part in this density regions.

Reversible part is the density regions generated in the case where applying stress small (1.5MPa), and is answered by release Power and disappear and restore original uniform density distribution.Here, apply stress it is small in the case where the density regions that generate be Its density is not less than 0.1 times of the averag density of the crosslinked rubber composition before stretching and no more than the crosslinking rubber group before stretching Close 0.8 times of region of the averag density of object.By evaluating the distribution of the reversible part, rubber survey can be highly precisely evaluated Test piece.

Irreversible part is the density regions generated in the case where applying stress big (3.0MPa), wherein being crosslinked rubber The internal structure (bonding of strand) of composition is partly by stress rupture, even if density regions are protected after stress release It stays and does not restore reset condition.Here, in irreversible part, gap section be internal structure be extremely broken and its density not Less than 0 times and being averaged no more than the crosslinked rubber composition before stretching of the averag density of the crosslinked rubber composition before stretching 0.8 times of region of density.By evaluating the distribution of the gap section, rubber testing piece can be highly accurately evaluated.

The volume of density regions when to by the stretching of the applications stress of 1.5MPa and pass through the application stress of 3.0MPa The evaluation method of the volume of gap section when stretching is not particularly limited, as long as cross-linked rubber composition when stretching can be evaluated The Density Distribution of object can, it is preferable to use X ray computer tomography evaluation method.

The close of crosslinked rubber composition when stretching is evaluated in description using X ray computer tomography with reference to the accompanying drawings Spend the method for distribution.Fig. 1 is the perspective illustration of one embodiment of evaluating apparatus used in evaluation method.As shown in Figure 1 Evaluating apparatus 1 include stress bringing device 2, filming apparatus 3 and evaluating apparatus 4.

Stress bringing device 2 applies stress and is used to stretch rubber testing piece 10, low to generate inside rubber testing piece 10 Density area.

Preferably, stress bringing device 2 includes a pair of of fixture 21 and 22 for fixing testing piece 10, for making fixture 21 and fixture 22 move relative to each other, thus to testing piece 10 apply stress driving device 23.It is fixed in a fixture 21 In the case where, driving device 23 allows another fixture 22 to move up in the axis of testing piece 10.Therefore, can apply makes to test The stress that piece 10 stretches in its axial direction.

The stress in testing piece 10 is applied to detections such as load cell (not shown).The position of load cell and type can Selection of land selection.Scheduled stress is applied to rubber testing piece 10 using stress bringing device 2.Driving device 23 is configured to make Obtaining rubber testing piece 10 and fixture 21,22 can rotate relative to the axis of rubber testing piece 10.

Filming apparatus 3 by x-ray bombardment to testing piece 10 to shoot projected image.Filming apparatus 3 has for irradiating X The X-ray tube 31 of ray and for detecting X-ray and being converted into the detector 32 of electric signal.When rubber testing piece 10 and folder When tool 21,22 is rotated relative to the axis of rubber testing piece 10, filming apparatus 3 shoots multiple projected images, and can obtain The projected image on the entire periphery of testing piece 10.

Detector 32 has the fluorophor 32a for X-ray to be converted to visible light.The die-away time of fluorophor 32a is excellent It is selected as 100ms or less.In the case where the die-away time of fluorophor 32a being more than 100ms, when testing piece 10 is equal relative to testing piece While 10 axis rotation when being continuously shot multiple projected images, the ghost of the projected image shot before may be to wanting later The projected image of shooting has an adverse effect.From this viewpoint, the die-away time of fluorophor 32a be more preferably 50ms with Under, further preferably 10ms or less.

Evaluating apparatus 4 evaluates the performance of crosslinked rubber composition based on the Density Distribution determined by projected image.For Evaluating apparatus 4, such as appliance computer 40.Computer 40 includes main body 41, keyboard 42 and display device 43.The main body 41 setting There is such as central processing unit (CPU), ROM operates the storage device of memory and hard disk.According to the present embodiment for holding The treatment process (program) of row analogy method has been stored in advance in the storage device.

Fig. 2 is to indicate that in-service evaluation device 1 evaluates the processing of the method for Density Distribution when crosslinked rubber composition stretches The flow chart of step.The evaluation method of Density Distribution includes applying stress to rubber testing piece 10 to produce in rubber testing piece 10 The step S1 and S2 of raw density variation (density regions) with x-ray bombardment rubber testing piece 10 and shoot the bat of projected image Step S3 and S4 are taken the photograph, and evaluate based on the Density Distribution determined by projected image the Density Distribution of crosslinked rubber composition Evaluation procedure S5 and S6.

In step sl, rubber testing piece 10 is fixed on fixture 21,22.

The shape of rubber testing piece 10 is not particularly limited, but since rubber testing piece 10 has symmetry and can hold It changes places and obtains the measurement result of high reproducibility, it is more preferably cylindric it is advantageous to be cylindric or cuboid shape.

The diameter of rubber testing piece 10 is preferably five times of its axial length, more preferably ten times, further preferably two Ten times.According to such testing piece 10, when applying stress to rubber testing piece 10, the deformation of the side of rubber testing piece 10 by To limitation.As a result, the volume of rubber testing piece 10 increases, and very big answer is applied with inside rubber testing piece 10 Power.Therefore, density regions are easy to produce in testing piece 10, can quickly and easily evaluate the performance of elastic material.

Rubber testing piece 10 is fixed between the two with the state between two fixtures 21,22.Rubber testing piece 10 Upper surface is fixed on the lower surface of fixture 21, and the lower surface of testing piece 10 is fixed on the upper surface of fixture 22.It can be with Fixing means is properly selected according to test environment etc..For example, can be fixed with adhesive or the elasticity by constituting testing piece 10 It is adhesively fixed caused by the vulcanization of material.Further, testing piece 10 can by respectively in upper and lower surfaces and Corresponding bonding part and connection joining part point are set on lower surface and upper surface, and are fixed to fixture 21, on 22.

In step s 2, as shown in Figure 1, fixture 21 and fixture 22 are along the axial movement of rubber testing piece 10, i.e. fixture 22 It is moved along the direction far from fixture 21, so that rubber testing piece 10 be made to stretch.If stress is more than facing for crosslinked rubber composition Dividing value then generating density variation in rubber testing piece 10, and generates density regions in the inside of testing piece 10.

In the present invention, in order to determine with it is lesser application stress caused by density regions distribution, for stretching The stress of testing piece 10 is 1.5MPa.Further, in order to determine under biggish application stress among the density regions that generate Gap section (region of internal structure extreme damage) distribution, for extension test piece 10 stress be 3.0MPa.

In step s3, X-ray is irradiated on rubber testing piece 10 from X-ray tube 31.X-ray passes through rubber testing piece 10 And it is detected by detector 32.The X-ray that detector 32 will test is converted into electric signal and the electric signal is output to computer 40。

The brightness of the X-ray on rubber testing piece 10 and the S/N of X-ray scattering data are irradiated to than close from X-ray tube 31 Cut phase is closed.In the case where the brightness of X-ray is small, there are the trend that signal strength is weaker than the statistical error of X-ray, and even if Increase time of measuring, it may be difficult to obtain the data for showing S/N ratio good enough.From this view point, X-ray is bright Degree preferably 10¹⁰Photon/s/mrad²/mm²/ 0.1%bw or more.

In step s 4, the electric signal exported from detector 32 is handled by computer 40 to obtain projected image.

In step s 5, projected image is rebuild to obtain the three-dimension disclocation figure of rubber testing piece 10 by computer 40.Then In step s 6, Density Distribution of the crosslinked rubber composition when stretching can be evaluated according to tomograph, and can obtain can The volume of inverse part and gap section.

As described above, the glass transition temperature (Tg) of crosslinked rubber composition of the invention is -20 DEG C or less.It realizes and hands over Glass transition temperature after connection after rubber composition crosslinking is that the methods of -20 DEG C of conditions below is, such as using with low The method of the rubber components and plasticizer of glass transition temperature.The example packet of rubber components with lower glass transition temperatures Include the SBR with low styrene-content and contents of ethylene.

Tg is preferably -22 DEG C hereinafter, more preferably -24 DEG C or less.When the Tg of crosslinked rubber composition is in preferred scope When, rubber improves the tracing ability on uneven road surface.In addition, the lower limit of Tg is not particularly limited, if but due to Tg mistake Low, wet grip performance reduces, therefore Tg is preferably -40 DEG C or more, more preferably -30 DEG C or more.

Crosslinked rubber composition of the invention can be prepared by a conventional method, as long as crosslinked rubber composition is shown The volume of density regions when stretching and the volume of gap section are stated, and above-mentioned Tg can be obtained.For example, crosslinking rubber Glue composition can be prepared by the following method or by other methods: by the said components other than vulcanizing agent and vulcanization accelerator With Banbury mixer, kneading machine, then kneading machine well known to open roller etc., which be kneaded, is added vulcanizing agent and vulcanization promotes Agent is then further kneaded, is then vulcanized.

With more low when due to that can make the cross-linked state of crosslinked rubber composition uniformly and be easy to get stretching The rubber composition of gap section with small size when density area and stretching, it is preferred that the system included the following steps Preparation Method: cause rubber components, sulphur donor and sulfur atom-containing vulcanization accelerator mixing, then in obtained mixing product Filler is added and is kneaded under 120 DEG C or higher temperature.

Sulphur donor be for example under conditions of vulcanization (such as 150 DEG C, 1.5MPa) or be lower than conditions of vulcanization temperature and pressure The elementary sulfur or sulphur compound of active sulfur are discharged under power.In other words, the sulphur compound be conditions of vulcanization (such as 150 DEG C, The compound as vulcanizing agent function is typically exhibited under 1.5MPa) or under the temperature and pressure lower than conditions of vulcanization.Value It obtains it is noted that the active sulfur of this release forms a part of the side hanging structure described below.

The vulcanization accelerator of above-mentioned sulfur atom-containing indicates that the vulcanization accelerator comprising sulphur atom, the sulphur atom pass through singly-bound In conjunction with other molecules.In the vulcanization accelerator of sulfur atom-containing, there is those of release active sulfur vulcanization accelerator and do not discharge Those of active sulfur vulcanization accelerator does not discharge active sulfur from the viewpoint of the progress of cross-linking reaction in inhibition mixing process The vulcanization accelerator of sulfur atom-containing be preferred.

By the vulcanization accelerator for causing rubber components, sulphur donor and sulfur atom-containing before mixing rubber component and filler Mixing, absorption of the filler to the vulcanization accelerator of sulphur donor and sulfur atom-containing, therefore sulphur donor and sulfur atom-containing can be prevented Vulcanization accelerator can be effectively dispersed in rubber components.In the above preparation method, it adds filler to and passes through mixing In the mixing product that the vulcanization accelerator of rubber components, sulphur donor and sulfur atom-containing obtains, then in 120 DEG C or higher mixing At a temperature of be kneaded.Under the mechanical shear stress during 120 DEG C or higher melting temperature and mixing, active sulfur is released from sulphur donor It puts.Sulphur donor, the vulcanization accelerator and rubber components of sulfur atom-containing react to each other, and result in the vulcanization accelerator of sulfur atom-containing All or part of state of (hereinafter referred to as " vulcanization accelerator residue ") in conjunction with rubber components, that is, form wherein "-S- sulphur The state of side hanging structure of the change promotor residue " in conjunction with rubber components.In the reaction mechanism, thus it is speculated that the active sulfur discharged It is reacted with the sulphur atom of the vulcanization accelerator of sulfur atom-containing to be formed and there are two or more to be bonded the structure of sulphur atom, and The structure division is reacted with the double bond part of rubber components.By being kneaded in the state of forming side hanging structure, rubber group Divide and moved together with vulcanization accelerator residue, therefore the dispersion of the vulcanization accelerator residue in whole rubber composition can be improved The uniformity of state.Therefore, in the above preparation method, the uniformity of crosslink density when vulcanization can be improved.It should be noted that It is that melting temperature as used herein is the observed temperature of the rubber composition in kneading machine, and the surface temperature of rubber composition can To be measured by non-contact temperature sensor etc..

The preparation method is characterized in that, for example, (1) causes rubber components, sulphur donor and sulfur-bearing before being kneaded filler The mixing of the vulcanization accelerator of atom, and (2), after adding filler, being kneaded is 120 DEG C in melting temperature or more relative superiority or inferiority carries out. As long as meeting above-mentioned requirements, any material can be added in any step.For example, including step X and step F in mixing step In the case where the two steps, mixing step can be former to cause rubber components, sulphur donor and sulfur-bearing in the initial stage of step X The mixing of the vulcanization accelerator of son is added filler in the mid-term of step X, is kneaded under 120 DEG C or more of melting temperature, with Step F is carried out afterwards.In addition, including for example step X in mixing step, in the case where this 3 steps of step Y, step F, it is kneaded step It suddenly can be the mixing of initiation rubber components in stepx, the vulcanization accelerator of sulphur donor and sulfur atom-containing, in subsequent step Filler is added in Y and is kneaded under 120 DEG C or higher melting temperature, step F is then carried out.In addition, other include three The example of the mixing step of a step is also possible to cause rubber components, sulphur donor and sulfur atom-containing in the initial stage of step X Vulcanization accelerator mixing, step X mid-term add filler, be kneaded under 120 DEG C or higher melting temperature, with Step Y and step F is carried out afterwards, or be can be and caused rubber components, sulphur donor and sulfur atom-containing in the initial stage of step X The mixing of vulcanization accelerator adds filler in the mid-term of step X, in 120 DEG C or higher melting temperature in subsequent step Y Lower addition filler is simultaneously kneaded, and step F is then carried out.It should be noted that finishing scouring can be carried out between each step.

The temperature of the vulcanization accelerator of mixing rubber component, sulphur donor and sulfur atom-containing is not particularly limited.From inhibition sulphur From the perspective of the cross-linking reaction of donor and the vulcanization accelerator of sulfur atom-containing carries out, melting temperature is preferably shorter than 160 DEG C, more excellent Select 150 DEG C or less.

In addition, before filler is added into rubber components, the vulcanization accelerator of rubber components, sulphur donor and sulfur atom-containing Mixing time be not particularly limited.From the viewpoint of improving dispersibility, mixing time is, for example, 10 seconds or more.

From the viewpoint of inhibiting cross-linking reaction excessively to carry out, the melting temperature after adding filler is preferably 170 DEG C or less.

In addition, the mixing time after adding filler in rubber components and melting temperature being made to reach 120 DEG C is not special Limitation, from the point of view of improving dispersibility, for example, 2 minutes or more.Here, mixing time refers to from adding filler to rubber Until time point to the time point that the Overall Steps of mixing step terminate when melting temperature reaches 120 DEG C after in glue component Time.For example, melting temperature when reaching 120 DEG C after adding filler into rubber components in stepx, when mixing time is from this Between time of the point until the time point that step F terminates.

As set forth above, it is possible to use the sulphur compound of elementary sulfur and/or above-mentioned release active sulfur as sulphur donor.Elementary sulfur Example include powdery sulphur, precipitated sulfur, colloid sulphur is surface-treated sulphur, insoluble sulfur etc..

If an excess amount of elementary sulfur of mixture is as sulphur donor, vulcanization reaction may be carried out excessively in mixing step. Therefore, even if use elementary sulfur as sulphur donor, be 100 mass parts by rubber components in terms of, content is preferably 0.1 mass parts Below.On the other hand, from the viewpoint of breaking strength, content is preferably 0.05 mass parts or more.

The example of sulphur compound as sulphur donor includes by-(- M-S-C-)_nIndicate polymeric polysulfides and have Pass through-the S of two or more sulphur atoms of singly bound_n(n >=2) structure and the compound for discharging active sulfur.The compound Example include alkylphenol disulfides, morpholine disulphide has-S_nThiuram vulcanization accelerator (the curing of (n >=2) Tetra methylthiuram (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), curing are double Pentamethylene thiuram (DPTT) etc.), vulcanization accelerator such as 2- (4'- morpholine two is thio) benzothiazole (MDB) and more vulcanizations Object silane coupling agent (for example, the Si69 (bis- (3- triethoxysilylpropyltetrasulfide) tetrasulfides) manufactured by Degussa AG) With the sulphur compound indicated by following formula (1), (2) or (3).

R in formula¹It is identical or different, it indicates that there is 3-15 carbon atom and can have the monovalent hydrocarbon of substituent group, n table Show the integer of 2-6.

R in above formula (1)¹With 3 to 15 carbon atoms and to can have the monovalent hydrocarbon of substituent group, carbon atom number Preferably 5 to 12, more preferable 6 to 10.Monovalent hydrocarbon R¹It can be straight chain, branch or cricoid any, and can be full And/or any one of unsaturated alkyl (aliphatic, alicyclic or aromatic hydrocarbyl or other groups).Wherein, can preferably have The aromatic hydrocarbyl of substituted base.

Preferred R¹Example include C_3-15Alkyl, the C being substituted_3-15Alkyl, C_3-15Naphthenic base, the C being substituted_3-15Cycloalkanes Base, C_3-15Aralkyl, the C being substituted_3-15Aralkyl etc., wherein preferred aralkyl and the aralkyl being substituted.Here, alkyl Example includes butyl and octyl, and the example of naphthenic base includes cyclohexyl, and the example of aralkyl includes benzyl and phenethyl.Substituent group Example include polar group, such as oxo base (=O), hydroxyl, carboxyl, carbonyl, amino, acetyl group, amide groups and acid imide Base.

In addition, " n " in formula (1) is 2 to 6 integer, preferably 2 or 3.

In formula, R²It is identical or different, it indicates that there are 3~15 carbon atoms and can have the bivalent hydrocarbon radical of substituent group, " m " indicates 2~6 integer.

In above formula (2), R²It is that with 3 to 15 carbon atoms and can have the bivalent hydrocarbon radical of substituent group, and carbon Atomicity is preferably 3 to 10, more preferable 4 to 8.Bivalent hydrocarbon radical R²It can be straight chain, branch or cricoid any can be full And/or any one of undersaturated alkyl (aliphatic, alicyclic or aromatic hydrocarbyl or other groups).It wherein, preferably can be with Aliphatic alkyl with substituent group, more preferable linear aliphatic hydrocarbon groups.

R²Example include C_3-15Alkylidene, the C being substituted_3-15Alkylidene etc..Here, the example of alkylidene includes Aden The example of base, pentylidene, hexylidene, heptamethylene, octamethylene, nonylene etc., substituent group includes and R¹In identical substituent group.

In addition, the integer that " m " in formula (2) is 2~6, preferably 2 or 3.

The example of the sulfide indicated by above-mentioned formula (1) or (2) includes N, N'- bis- (butyrolactam) disulphide, N, N'- bis- (5- methyl-butyrolactam) disulphide, N, N'- bis- (5- ethyl-butyrolactam) disulphide, N, N'- bis- (5- isopropyl-butyrolactam) disulphide, N, N'- bis- (5- methoxyl group-butyrolactam) disulphide, N, N'- bis- (5- ethyoxyl-butyrolactam) disulphide, N, N'- bis- (the chloro- butyrolactam of 5-) disulphide, (the 5- nitre of N, N'- bis- Base-butyrolactam) disulphide, N, N'- bis- (5- amino-butyrolactam) disulphide, (the acyl in δ-penta of N, N'- bis- Amine (balerolactam)) disulphide, N, N'- bis- (δ-caprolactam) disulphide, two sulphur of N, N'- bis- (epsilon-caprolactams) Compound, N, N'- bis- (3- methyl-δ-caprolactam) disulphide, N, N'- bis- (3- ethyl-epsilon-caprolactams) disulphide, N, N'- bis- (3- isopropyl-epsilon-caprolactams) disulphide, N, N'- bis- (δ-methoxyl group-epsilon-caprolactams) disulphide, N, N'- Two (3- ethyoxyl-epsilon-caprolactams) disulphide, N, N'- bis- (the chloro- epsilon-caprolactams of 3-) disulphide, (δ-nitre of N, N'- bis- Base-epsilon-caprolactams) disulphide, N, N'- bis- (3- amino-e-caprolactam) disulphide, (the acyl in ω-seven of N, N'- bis- Amine) disulphide, N, N'- bis- (ω-eight lactams) disulphide, dicaprolactam disulfide, morpholine disulphide, N- benzyl Base-N- [(dibenzyl amino) disulphanes base] phenylmethanamine (N, N'- bis- thio two (dibenzylamine)) etc..These sulfide can be single It solely uses, two or more can also be applied in combination.

R in formula³It is identical or different, and indicate alkyl, benzothiazolyl, amino, morpholinyl, dialkyl amino first Acyl group or the group indicated by following formula (4)." k " indicates 2 to 6 integer.

R in formula⁴It is identical or different, indicate alkyl, benzothiazolyl thioether group, naphthenic base or hydrogen atom.

R in above-mentioned formula (3)³It is identical or different, indicate alkyl, benzothiazolyl, amino, morpholinyl, dialkyl Group shown in carbamoyl or above-mentioned formula (4).Wherein, preferably there is the alkyl for 1~10 carbon atom, benzothiazole (alkyl is identical or different, for for 1~10 carbon atom for base, amino, morpholino base or dialkyl carbamoyl Alkyl).

Alkyl in dialkyl carbamoyl with 1-10 carbon atom and the alkane with 1-10 carbon atom The example of base includes methyl, ethyl, n-propyl, isopropyl, normal-butyl, isobutyl group, sec-butyl, tert-butyl, amyl, hexyl, heptan Base, 2- ethylhexyl, octyl, nonyl etc..

As R in above-mentioned formula (3)³Identical or different preferred example, including benzothiazolyl, morpholino base, two Alkylthio carbamoyl (alkyl is identical or different, is the alkyl with 1~5 carbon atom).In above-mentioned formula (3) R³Identical or different further preferred example, including benzothiazolyl or the dialkyl carbamoyl (alkyl It is identical or different, be the alkyl with 1~5 carbon atom).

" k " in formula (3) is 2 to 6 integer, and further preferred 2 or 3.

R in above-mentioned formula (4)⁴Identical or different, respectively alkyl, benzothiazolyl sulfide group, naphthenic base or hydrogen are former Son.Alkyl is preferably the alkyl with 1 to 10 carbon atom, and naphthenic base is preferably the cycloalkanes with 1 to 5 carbon atom Base.

As the example for the sulphur compound that formula (3) indicate, including tetramethylthiuram disulfide, the tetramethyl autumn is blue Nurse, tetrabutylthiuram disulfide, 2- (morpholine two is thio) benzothiazole, dibenzothiazyl disulfide, N- cyclohexyl -2- benzo Thiazolyl sulfenamide etc., and can be suitably using diphenyl disulfide and dithiazole.These can be used alone or can It is applied in combination with two or more.

When using the sulphur compound for playing sulphur donor function, for accelerating the reason of forming side hanging type structure, with rubber Group is divided into 100 mass parts meters, and content is preferably not less than 0.1 mass parts, more preferably no less than 0.2 mass parts.On the other hand, from From the perspective of inhibiting gelation when being kneaded, content is preferably that 5 below the mass, more preferably 3 below the mass, into one Step preferably 2 is below the mass.

The vulcanization accelerator for playing sulphur donor function includes with the sulphur by singly-bound and the sulphur atom of other molecular linkages Change promotor.Therefore, the vulcanization accelerator for playing the sulfur atom-containing of sulphur donor function has the vulcanization of sulphur donor and sulfur atom-containing The function of both promotors, and by mixture largely play sulphur donor function single sulfur atom-containing vulcanization accelerator or Person is by being applied in combination two or more this vulcanization accelerators, it is possible to create side hanging type structure.But at mixed a large amount of To the sulfur atom-containing of sulphur donor function vulcanization accelerator when, cross-linking reaction can be carried out excessively when mixing, be risen in mixed a small amount of To the sulfur atom-containing of sulphur donor function vulcanization accelerator when, it is difficult to acquisition make the uniform effect of crosslink density.Therefore, it is adding The vulcanization accelerator of the sulphur donor and sulfur atom-containing that are kneaded before filler be preferably sulphur donor (play sulphur donor and/or its The vulcanization accelerator of the sulfur atom-containing of the function of his sulphur donor) and do not discharge sulphur sulfur atom-containing vulcanization accelerator.

The vulcanization accelerator for not discharging the sulfur atom-containing of sulphur is under conditions of vulcanization (such as 150 DEG C, 1.5MPa) or low The vulcanization accelerator of the sulfur atom-containing of sulphur is not discharged under the temperature and pressure of conditions of vulcanization.In other words, this not discharge sulphur Sulfur atom-containing vulcanization accelerator be under conditions of vulcanization (such as 150 DEG C, 1.5MPa) or be lower than conditions of vulcanization temperature With the vulcanization accelerator for the sulfur atom-containing for not showing the function as vulcanizing agent under pressure.

The example for not discharging the vulcanization accelerator of the sulfur atom-containing of sulphur includes thiazole system vulcanization accelerator (2- sulfydryl benzo thiophene Azoles (MBT), the zinc salt (ZnMBT) of 2-mercaptobenzothiazole, cyclohexylamine salt (CMBT) of 2-mercaptobenzothiazole etc.)；Sulfenyl Amine system vulcanization accelerator (N- cyclohexyl -2-[4-morpholinodithio sulfenamide (CBS), N- (tert-butyl) -2-[4-morpholinodithio sulfenamide (TBBS), N, N- dicyclohexyl -2-[4-morpholinodithio sulfenamide etc.)；The vulcanization of tetra methylthiuram monosulfide (TMTM) promotees Into agent；Dithiocarbamate system vulcanization accelerator (pentamethylene aminodithioformic acid piperidines (PPDC), dimethyl two Zinc thiocarbamate (ZnMDC), zinc diethyl dithiocarbamate (ZnEDC), zinc dibutyl dithiocarbamate (ZnBDC), N- ethyl, N-phenyl zinc dithiocarbamate (ZnEPDC), N- zinc pentamethylene dithiocarbamate (ZnPDC), NB sodium dibutyl dithiocarbamate (NaBDC), cupric dimethyldithio carbamate (CuMDC), dimethyl two Thiocarbamic acid iron (FeMDC), tellurium diethyl dithiocarbamate (TeEDC) etc.)；Etc..Notably, as Two -2-[4-morpholinodithio base sulfenamides (MBTS) of thiazole system vulcanization accelerator have-S_n(n >=2), and be release sulphur Vulcanization accelerator, but in the case where usual combined amount the function as vulcanizing agent is not shown to natural rubber and butadiene rubber Can, therefore can equally be used with the vulcanization accelerator for the sulfur atom-containing for not discharging sulphur.

For the reason of vulcanization reaction is effectively performed in vulcanisation step, be 100 mass parts by rubber components in terms of, sulfur-bearing The content of the vulcanization accelerator of atom is preferably not less than 1.0 mass parts, more preferably no less than 1.5 mass parts.On the other hand, from suppression From the point of view of incipient scorch and precipitating on rubber surface processed, content is preferably more than 5 mass parts, more preferably no more than 3 mass Part.

In the above preparation method, preferably filler is being added in rubber components and at 120 DEG C or higher mixed After being kneaded at a temperature of refining, it is further kneaded additional sulphur donor.By adding additional sulphur donor, inhibit to hand over during milling Join overreact to carry out, while cross-linking reaction can be carried out sufficiently during vulcanization.

After being kneaded in adding filler to rubber components and under 120 DEG C or higher melting temperature, subsequent Step F in add additional sulphur donor.What additional sulphur donor was kneaded before can be and adding filler to rubber components Congener sulphur donor, or can be different types of sulphur donor.The example includes elementary sulfur such as powdery sulphur, precipitated sulfur, glue Body sulphur is surface-treated sulphur, insoluble sulfur etc..

The content of additional sulphur donor is not particularly limited, the reason being effectively performed for vulcanization reaction in vulcanisation step By, by rubber components be 100 mass parts in terms of, content is preferably 0.5 mass parts or more, more than more preferably 0.8 mass parts.Separately On the one hand, the reason excellent for wearability, content are preferably no greater than 3.0 mass parts, more preferably no more than 2.5 mass parts.

When adding additional sulphur donor in step F, common vulcanization accelerator can be added.Common vulcanization promotes The example of agent includes the thiuram system disulphide and polysulfide of the vulcanization accelerator as sulfur atom-containing；As not sulfur-bearing original The guanidine system of the vulcanization accelerator of son, aldehyde-amine system, aldehyde-ammonia system and imidazoline system vulcanization accelerator；Etc..

By rubber components be 100 mass parts in terms of, the content for the vulcanization accelerator being added in step F is preferably not less than 0.1 Mass parts.The blend amount for the vulcanization accelerator being added in step F and to be mixed before filler is added to rubber components The mass ratio of the blend amount of the vulcanization accelerator of sulfur atom-containing is preferably higher than 0% and no more than 80%, further preferably less In 60%.When the mass ratio is not more than 80%, it can obtain and inhibit coking and there is excellent fracture resistance and wearability Crosslinked rubber composition.

Crosslinked rubber composition of the invention can be not only used for tyre element such as tyre surface, bottom tyre surface, carcass, side wall and Tire bead, can be also used for vibration-proof rubber, band, other rubber products in hose and rubber industry.Particularly, have by this The tire for the tyre surface that the crosslinked rubber composition of invention is constituted is but preferred due to excellent wearability.

Uncrosslinked rubber composition can be used with usually side using the tire that crosslinked rubber composition of the invention manufactures Method manufactures.That is, tire can manufacture in the following way: as needed by above-mentioned additive and diene rubber component mixture and Uncrosslinked rubber composition is prepared, uncrosslinked rubber composition extrusion is processed into the shapes such as tyre surface, then in tyre building machine It is upper laminated together with other tyre elements, and formed by conventional shaping method, to form unvulcanized tire, and vulcanizing The unvulcanized tire is heated and compressed in machine.

The structure of pneumatic tire of the invention is not particularly limited, and can be the structure of conventional pneumatic tire.That is, Pneumatic tire of the invention can be manufactured by using the component manufactured by crosslinked rubber composition of the invention, which is Constitute at least one component in the tyre element with the pneumatic tire of traditional structure.Particularly preferred pneumatic tire includes difference The bead core that is arranged in pair of right and left bead part extends to two bead parts via two sides wall portion from crown part and is fixed on The liner layer located more in the inner part on tire diameter direction than the casingply is arranged in the casingply of the bead core And the tyre surface at place more more outward than the casingply on tire diameter direction is set, the tyre surface, which has, to be passed through When applying the volume of 35% or more density regions when stress stretches, being stretched through the application stress of 3.0MPa of 1.5MPa The volume of 7.5% gap section below and -20 DEG C of glass transition temperatures below.It should be noted that above-mentioned tyre surface be with The part of road surface contact, and be made of and at least one hand over two or more different crosslinked rubber compositions in tyre surface In the case where joining rubber composition for crosslinked rubber composition of the present invention, tire obtained is tire of the invention.

Embodiment

Will be based on the embodiment description present invention, but the present invention is not limited only to this.

It is explained below the various chemicals used in embodiment and comparative example.

SBR1: (S-SBR, styrene-content: 26 mass %, vinyl are prepared according to the aftermentioned method for preparing modified SBR1 Content: 59%, Tg:-25 DEG C, Mw:4 × 10⁵)

SBR2: manufactured by ZEON CORPORATION Nipol 1502 (E-SBR, styrene-content: 23.5 mass %, Contents of ethylene: less than 20%, Tg:-54 DEG C, Mw:5 × 10⁵)

BR: by Ube Industries, the BR150B of Ltd. manufacture

Silica: the ULTRASIL VN3 (N manufactured by Evonik Degussa₂SA:175m²/g)

Silane coupling agent: Si266 (bis- (3- triethoxysilylpropyltetrasulfides) two sulphur manufactured by Evonik Degussa Compound)

Carbon black: the DIABLACK I (N manufactured by Mitsubishi Chemical Corporation₂SA:98m²/ g, DBP Oil absorption: 124ml/100g)

Zinc oxide: the zinc oxide No.2 manufactured by Mitsui Mining&Smelting Co., Ltd.

Stearic acid: the stearic acid pearl " Tsubaki " manufactured by NOF

Antioxidant: OZONONE 6C (N- (1, the 3- dimethyl butyrate manufactured by Seiko Chemical Co., Ltd. Base)-N- phenyl-pphenylenediamine, 6PPD)

Oil: by Idemitsu Kosan Co., the Diana Process oil AH-24 of ltd. manufacture.

Elementary sulfur: by Tsurumi Chemical Industry Co., the powder sulphur of Ltd. manufacture

Vulcanization accelerator: by OUCHI SHINKO CHEMICAL INDUSTRIAL CO., the Nocceler of LTD. manufacture NS (TBBS N- tert-butyl -2-[4-morpholinodithio base sulfenamide)

Sulphur donor: Rhenogran CLD80 (the caprolactam curing manufactured by Rhein Chemie Corporation Object)

The various chemicals of preparation method explained below for SBR1.

Hexamethylene: by Kanto Chemical Industry Co., the hexamethylene of Ltd. manufacture

Pyrrolidines: by Kanto Chemical Industry Co., the pyrrolidines of Ltd. manufacture

Divinylbenzene: the divinylbenzene manufactured by SIGMA-ALDRICH JAPAN

1.6M lithium hexane solution: by Kanto Chemical Industry Co., the positive fourth of 1.6M of Ltd. manufacture Base lithium hexane solution

Isopropanol: by Kanto Chemical Industry Co., the isopropanol of Ltd. manufacture

Styrene: by Kanto Chemical Industry Co., the styrene of Ltd. manufacture

Butadiene: by TAKACHIHO CHEMICAL INDUSTRIAL CO., the 1,3-butadiene of LTD. manufacture

Tetramethylethylenediamine: the N, N, N' manufactured by Kanto Chemical Industry Co., Ltd., N'- tetramethyl Ethylenediamine

Modifying agent: 3- (N, the N- dimethylaminopropyl) trimethoxy silane manufactured by Azmax Co.

The preparation method of SBR1

In the 100ml container that nitrogen is sufficiently displaced from, hexamethylene 50ml, pyrrolidines 4.1ml and divinylbenzene is added Then 1.6M lithium hexane solution 0.7ml is added in 8.9ml into mixture, stir at 0 DEG C.After 1 hour, isopropyl is added Alcohol terminates reaction, then extracts and refines to obtain monomer-A.Then, in the 1000ml pressure vessel that nitrogen is sufficiently displaced from, Addition 600ml hexamethylene, 12.6ml styrene, 71.0ml butadiene, 0.06g monomer-A and 0.11ml tetramethylethylenediamine, and 0.2ml 1.6M lithium hexane solution is added into the mixture, is then stirred at 40 DEG C.After 3 hours, 0.5ml is added Modifying agent stirs mixture.After 1 hour, 3ml isopropanol is added and terminates polymerization.2,6- tert-butyl pair is added into reaction solution After cresols 1g, reprecipitation processing is carried out to solution with methanol, then heat drying, obtains SBR1.

Embodiment 1~13 and comparative example 1~3

It is formulated according to mixture shown in table 1 and 2, by various chemicals shown in step X in 1.7L Banbury mixing 5.0 minutes (step X) is kneaded in machine under 100 DEG C of discharge temperatures.It then, will be in mixing product and step Y obtained in step X Shown in various chemicals with 1.7L Banbury mixer not less than 140 DEG C at a temperature of be kneaded 30 seconds, and in 150 DEG C of row It is further kneaded at a temperature of out 3 minutes (step Y).It then, will be each shown in the mixing product obtained in step Y and step F Kind chemicals is kneaded 3 minutes with open roller at about 80 DEG C to obtain unvulcanized rubber composition (step F).It is special using having Obtained unvulcanized rubber composition extrusion molding is tyre surface form by the extruder of extrusion nozzle of shape of shaping, and by extrudate With other tyre elements be laminated to form unvulcanized tire, then at 170 DEG C press cure 12 minutes with production test tire (tire size: 195/65R15).Following evaluation is carried out using obtained test tire.Evaluation result is shown in tables 1 and 2.

The volume of density regions

There is the cylindrical rubber testing of 10mm diameter and 1mm height by the tread portion preparation of cutting test tire Piece, and each rubber testing piece is fixed on fixture shown in FIG. 1 and starts the stretching of testing piece.In applying with 1.5MPa While adding stress to be stretched, X-ray irradiation (brightness: 10¹⁶Photon/s/mrad²/mm²/ 0.1%bw), it is disconnected to carry out computer Layer photography.According to the Density Distribution that three-dimensional tomographic image prepared by the image by rebuilding shooting obtains, to calculate stretching The volume ratio of density regions in rubber testing piece.It should be noted that X ray computer tomography is synchronous in large size It is carried out in radiation appliance SPring-8Beamline BL20B2, and P43 (Gd₂O₂S:Tb) (wherein when the decaying of fluorophor Between be 1ms) be used as fluorophor.It is by passing through convolution together for 200 with a thickness of 10 microns of faultage image stacking that CT, which is rebuild, What back projection method (Convention Back Projection Method) carried out.It is assumed that the rubber experiment piece before stretching Averag density is 1, then density regions are the regions that density is 0.1~0.8.

The volume of gap section

There is the cylindrical rubber testing of 10mm diameter and 1mm height by the tread portion preparation of cutting test tire Piece, and each rubber testing piece is fixed on fixture shown in FIG. 1 and starts the stretching of testing piece.In applying with 3.0MPa When stress being added to stretch, X-ray irradiation (brightness: 10¹⁶Photon/s/mrad²/mm²/ 0.1%bw), carry out computer tomography. According to the Density Distribution that three-dimensional tomographic image prepared by the image by rebuilding shooting obtains, to calculate the rubber testing of stretching The volume ratio of gap section in piece.It should be noted that X ray computer tomography is in large-scale Synchrotron Radiation It is carried out in SPring-8Beamline BL20B2, and P43 (Gd₂O₂S:Tb) (wherein the die-away time of fluorophor is 1ms) As fluorophor.CT reconstruction is by stacked together by convolution projection method with a thickness of 10 microns of faultage image by 200 (Convention Back Projection Method) is carried out.Assuming that the averag density of the rubber testing piece before stretching It is 1, then gap section is the region that density is 0 to 0.1.

Glass transition temperature

Rubber testing piece is prepared by the tread portion of cutting test tire, using by Iwamoto Seisakusyo K.K. the viscoelastic spectrometer manufactured tests to obtain the temperature distribution history of the tan δ of each rubber testing piece, and test condition is The frequency of 10Hz, 10% initial strain, the heating rate of ± 0.25% amplitude and 2 DEG C/min, with temperature obtained point The corresponding temperature of maximum tan δ value in cloth curve is confirmed as glass transition temperature (Tg (DEG C)).

Wearability

It is loaded on the four wheels of household FF vehicle by each test tire that method same as described above produces, and And after the vehicle driving of 8000km, the depth of the groove of each tyre tread part is measured.According to the groove depth of four wheels The arithmetic mean of instantaneous value of degree is calculated when the groove depth of tire reduces the operating range of 1mm.Assuming that the abrasion resistance index of comparative example 1 is 100, the result of each mixture formula is indicated by following formula with index (abrasion resistance index).Abrasion resistance index is bigger, and wearability is better.

Abrasion resistance index=(tire groove depth reduces operating range when 1mm)/(tire groove depth reduces ratio when 1mm Compared with the operating range of example 1) × 100

Table 1

Table 2

Embodiment 14 to 16

According to the formula of mixture shown in table 3 and discharge temperature and time, with institute in 1.7L Banbury mixer mixing step X The chemicals (step X) shown.Then, by chemicals 1.7L class primary shown in the mixing product obtained in step X and step Y In mixer discharge temperature shown in table 3 and be kneaded under the time, and be further kneaded 3 minutes at 150 DEG C of discharge temperature (step Y).Then, under the discharge temperature shown in table 3 and time (step F), the mixing product and step that will be obtained in step Y Chemicals shown in F is kneaded with open roller to obtain unvulcanized rubber composition.It is sprayed using the extrusion with specific shape Obtained unvulcanized rubber composition extrusion molding is tyre surface form by the extruder of mouth, and by extrudate and other tyre elements Lamination to form unvulcanized tire, then at 170 DEG C press cure 12 minutes with production test tire (tire size: 195/ 65R15).Following evaluation is carried out using the test tire of acquisition.Evaluation result is as shown in table 3.

Table 3

Can be seen that pneumatic tire of the invention from result shown in table 1 to 3 includes tyre surface, and the tyre surface has 1.5MPa's applies the density regions of large volume when stretching under stress, the sky for applying small size when stress stretches in 3.0MPa Gap part and lower glass transition temperatures, crosslinked rubber composition of the invention has to be stretched under the application stress of 1.5MPa When large volume density regions, 3.0MPa apply stress stretch when small size gap section and reduced TG transformation Temperature, the pneumatic tire and crosslinked rubber composition are the pneumatic tire and crosslinking rubber for being respectively provided with excellent wearability Composition.

Claims

1. pneumatic tire characterized by comprising be separately positioned on bead core in pair of right and left bead part, passed through from crown part Two bead parts are extended to by two sides wall portion and is fixed on the casingply of the bead core, is arranged on tire diameter direction The liner layer located more in the inner part than the casingply and it is arranged on tire diameter direction more than the casingply The tyre surface located in the outer part, the tyre surface have the body of 35% or more density regions when stretching under the application stress of 1.5MPa The volume of 7.5% gap section below, -20 DEG C of glass transitions below when being stretched under application stress long-pending, in 3.0MPa Temperature,

The density regions are 0.1~0.8 times of the region that density is the density of crosslinked rubber composition before stretching, the sky Gap part is 0~0.1 times of the region that density is the density of crosslinked rubber composition before stretching.

2. crosslinked rubber composition has the body of 35% or more density regions when stretching under the application stress of 1.5MPa Product, the volume and -20 DEG C of glass transitions below of 7.5% gap section below when being stretched under the application stress of 3.0MPa Temperature,

3. crosslinked rubber composition according to claim 2, wherein with when being stretched under the application stress of 1.5MPa The volume of 40% or more density regions.

4. crosslinked rubber composition according to claim 2, wherein with when being stretched under the application stress of 1.5MPa The volume of 50% or more density regions.

5. crosslinked rubber composition according to claim 2, wherein with when being stretched under the application stress of 1.5MPa The volume of 60% or more density regions.

6. crosslinked rubber composition according to claim 2, wherein with when being stretched under the application stress of 1.5MPa The volume of 70% or more density regions.

7. crosslinked rubber composition according to claim 2, wherein with when being stretched under the application stress of 1.5MPa The volume of 72% or more density regions.

8. the crosslinked rubber composition according to any one of claim 2~7, wherein have -22 DEG C of glass below Change transition temperature.

9. the crosslinked rubber composition according to any one of claim 2~7, wherein have -24 DEG C of glass below Change transition temperature.

10. the crosslinked rubber composition according to any one of claim 2~7, wherein have -25 DEG C of glass below Glass transition temperature.

11. the crosslinked rubber composition according to any one of claim 2~7, wherein have -28 DEG C of glass below Glass transition temperature.

12. the crosslinked rubber composition according to any one of claim 2~7, wherein the crosslinked rubber composition Comprising rubber components, the rubber components include conjugated diene compound.

13. the crosslinked rubber composition according to any one of claim 2~7, wherein in the application stress of 1.5MPa The volume of density regions when lower stretching is from the cross-linked rubber composition when stretching for using X ray computer tomography What the Density Distribution of object calculated, the volume of the gap section under the applications stress of 3.0MPa when stretching is from using roentgenometer What the Density Distribution of the crosslinked rubber composition when stretching of calculation machine tomography calculated.

14. crosslinked rubber composition according to claim 13, wherein use the stretching of X ray computer tomography When the Density Distribution of crosslinked rubber composition evaluated by the evaluating apparatus with filming apparatus, the filming apparatus tool There is the X-ray tube of X-ray irradiation and detect X-ray and be converted into the detector of electric signal, the detector, which has, to be used for X-ray is converted to the fluorophor of visible light, the die-away time of the fluorophor is 100ms or less.

15. crosslinked rubber composition according to claim 14, wherein the brightness for the X-ray irradiated from the X-ray tube It is 10¹⁰Photon/s/mrad²/mm²/ 0.1%bw or more.

16. pneumatic tire characterized by comprising be separately positioned on bead core in pair of right and left bead part,

From crown part via two sides wall portion extend to two bead parts and be fixed on the bead core casingply,

Be arranged in the liner layer located more in the inner part on tire diameter direction than the casingply and

The tyre surface at place more more outward than the casingply on tire diameter direction is set, and the tyre surface is by claim 3 Crosslinked rubber composition described in any one of~15 is constituted.